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' i i @www R. H. DICK AND P. W. WIGGINTON.

HEAT HESISTING CABINET.

APPLICATION FILED NOV.24. |915. 1,325,624, Patented Dec. 23,1919.

2 SHEETS-SHEET I. l 2 S 2L /g Arron/ver I Ol n. H. DICK AND P. w. wIGGINToN.

Hm RSISTING CABINET. APPLICATION FILED NOV. 24. |915.

Patented Dec. 23, 1919.

2 SHEETS-SHEET 2- UN ITEI) STATES PATT OFFICE.

RALPH I-I. DICK AND PETER W. WIGGINTON, OF MARIETTA, OHIO, ASSIGNORS TO THE SAFE CABINET CO., 0F MARIETTA,

OHIO, A CORPORATION OF OHIO.

HEAT-RESISTING CABINET.

Application filed November 24, 1915.

To all whom t may concern:

Be it known that we, RALPH H. DICK and PETER IV. VIGGINTON, citizens of the United States, and residents of Marietta, vWashington county, State of Ohio, have invented a new and useful Heat-Resisting Cabinet, of which the following is a specification.

Our invention relates to improvements in heat resisting cabinets and its principal object is to increase the resistance to the entrance of heat in devices of this nature without materially increasing the weight or cost of the structure, to the end that Very high temperatures may be withstood for a long period of time, without damage of any kind being inflicted upon the contents thereof.

Such a structure must possess strength and rigidity, its various parts when assembled must be held together firmly and in such a manner that buckling from heat will be prevented, and in addition it must possess an impact resistance sufficient to guard against falls or damage that might be caused by other articles or materials falling upon the cabinet.

IVe have discovered that what has heretofore been considered a point in the construction where the resistance to the entrance of heat was greatest is in reality one of the weakest parts of the structure, namely, the line of juncture where the side walls join the front, or back walls, and also the line of juncture where any of the vertical walls join with either of the horizontal walls.

In the drawings herewith, Figure 1 is a horizontal sectional view of a cabinet.

Fig. 2 is a fragmentary sectional view taken through the juncture of the top wall and the front wall or door.

Fig. 3 is a fragmentary sectional view taken through the juncture of the top wall and one of the side walls.

Fig. t is a view showing how, in a cabinet the outer walls of which are of uniform thickness, the juncture lines are weak points, through which conduction of heat will take place more rapidly than through the sides, all other things being equal.

In Fig. 1, we show a regular form of heat resisting cabinet with outer side walls 10-10, outer back wall 11, outer front wall or doors 12-12, inner back wall 13, inner side walls 141-14 and inner front or door walls 15-15. The inner side walls in the corners at the front of the cabinet are Specication of Letters Patent.

Patented Dec. 23, 1919.

serial No. 63,349.

formed in angles, into which corresponding formations in the hinged ends of the doors are fitted, so that when the doors are closed, any heat which might enter from the eX- terior of the cabinet through the opening between the hinged end of the door and the adjacent front wall, would be obstructed in its passage to the interior, by the tortuous path it would be obliged to follow. lIhe usual dead air spaces to increase the insulation are indicated by the reference numbers 16-16.

In the preferred form shown herewith all of the walls referred to above are of sheet metal and the heat insulating material 18 between the outer and inner sheet metal walls is of the usual type with a low thermal conductivity and the qualities necessary to retard t-he progress of heat therethrough. The heat insulating material 17 in the corners of the structure is of the same general nature as to base, but should be made more dense and should have a relatively greater heat and fire resisting quality. As shown in Fig. 1, the top, bottom and side outside walls may be made in one piece with flanges for engagement with second flanges on the inner walls. IVe do not claim this construction of the cabinet walls in this application as it is covered in a previous patent.

The said material 17 in the corners of the structure for instance may be made of blocks containing 85% magnesium carbonate l and 15% asbestos fiber and the inigterial 18 between thewalls and not adjacent-to the corners may be asbestos air cell board, thereby obtaining a greater heat resistance in the corners where "it" is needed.

As shown in Fig. 1, the insulation between the interior and exterior of the cabinet is much heavier at the corner 17-17 than in the spaces indicated by the reference numerals 18-18.

We show in Fig. 4 how a cabinet constructed of material of uniform thickness and heat conductivity will have a weakness in its corners as to heat resistance, and also how heat will tend to enter the cabinet through the corners by conduction much more rapidly than through the part of the walls some distance away from the corners.

In this ligure 19-19 indicate the outer walls of a cabinet and 20-20 are the inner walls. At the point A on the inner side of the cabinet, removed some distance from the corners, heat will be received first from the point D, assuming that the heat surrounding the outer walls 19 is of the same degree.

At the same time, the point B at the inside corner will receive heat from the two surface points E and F and will therefore warm up more rapidly and attain a higher temperature than the point A. Any point along the line B C will have a higher temperature than any point not adjacent to the corners, as indicated by the isothermal lines Z1-22 but between the outer wall 19 and the inner wall 20 and the same distance from the said outer wall 19 as the said point on the line B C, for the reason that along the line B C the said point would be subjected to heat entering the space between E C and between C F, whereas in the space between the walls 19 and 20 not bounded by E C B F heat would enter only from one direction.

The median line 22 of the inner wall 20 will have the lowest temperature of that wall, and the temperature rises rapidly as the corners are approached.

Through a solid body of thickness D, area A, and conductivity K, on the opposite sides of which the temperature are respectively Tl and T2, the conduction of heat is indicated by the formula:

this greater resistance. There are many ways in which it can be done and we have shown herein only one of the preferred forms.

We claim:

1. A fire-heat resisting document-preserving cabinet or safe constructed with inner and outer sheet-metal walls and having insulations adapted to resist a charring or burning heat, the insulations at the corners being of higher heat resistance and the intermediate insulations between said corner insulations being of lower heat resistance, said higher resistance corner insulations being adapted respectively to resist the heat converging from two adjacent faces, and said intermediate insulations being adapted to resist the heat tending to enter from a single face of the structure, said differing insulations substantially equalizing the heat resistance of the structure.

2. A fire-heat resisting document-preserving cabinet or safe constructed with inner and outer sheet-metal walls and having insulations adapted to resist a charring or burning heat, the insulations at the corners being of higher heat resistance and theintermediate insulations between said corner insulations being of lower heat resistance, said higher resistance corner insulations eX- tending respectively beyond the thickness of the connected walls and being adapted respectively to resist the heat converging from two adjacent faces, and said intermediate insulations being adapted to resist the heat tending to enter from a single ,face of the structure, said differing insulations substantially equalizing the heat resistance of the structure.

RALPH H. DICK. PETER WV. VIGGINTON.

lVitnesses:

HARRIETT H. SPEAR, H. Gr. HEsLor. 

